High-strength titanium copper foil and method for producing same

Abstract

To provide a high-strength titanium-copper foil that is more suitable as a conductive spring material that can be used in electronic device components such as an autofocus camera module. A titanium copper foil containing Ti in an amount of 2.0 to 4.0 mass %, a remainder being copper and unavoidable impurities, said foil having a 0.2% yield strength of 1000 MPa or more and a spring limit value of 800 MPa or more in both directions parallel and perpendicular to a rolling direction, wherein no cracking occurs at bending radius/foil thickness=2 when a W bending test in conformity with JIS H3130: 2012 is performed at a width of 0.5 mm in a direction perpendicular to the rolling direction.

What is claimed is: 
     
       1. A titanium copper foil containing Ti in an amount of 2.0 mass% to 4.0 mass%, optionally containing one or more elements selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr in a total amount of 0 mass% to 1.0 mass%, a remainder being copper and unavoidable impurities, said foil having a 0.2% yield strength of 1000 MPa or more in both directions parallel and perpendicular to a rolling direction, and a spring limit value of 800 MPa or more in both directions parallel and perpendicular to the rolling direction, wherein no cracking occurs at bending radius/foil thickness =2 when a W bending test in conformity with JIS H3130: 2012 is performed at a width of 0.5 mm in a direction perpendicular to the rolling direction. 
     
     
       2. The titanium copper foil according to  claim 1 , having a 0.2% yield strength of 1100 MPa or more in both directions parallel and perpendicular to the rolling direction. 
     
     
       3. The titanium copper foil according to  claim 1 , having a spring limit value of 1000 MPa or more in a direction perpendicular to the rolling direction. 
     
     
       4. The titanium copper foil according to  claim 1 , wherein a thickness of the foil is 0.1 mm or less. 
     
     
       5. A method for producing titanium copper foil according to  claim 1  comprising steps of:
 making an ingot containing Ti in an amount of 2.0 mass % to 4.0 mass %, optionally containing one or more elements selected from the group consisting of Ag, B, Co, Fe, Mg, Mn, Mo, Ni, P, Si, Cr, and Zr in a total amount of 0 mass% to 1.0 mass%, a remainder being copper and unavoidable impurities; 
 sequentially performing hot and cold rolling on the ingot; 
 then performing a solution treatment for 5 seconds to 30 minutes at 700° C. to 1000° C.; 
 then performing cold rolling with 95% or more total rolling reduction under a condition of 10% or less rolling reduction per one pass; 
 then performing aging treatment in which a temperature is raised at a rate of 15° C/h or less and kept in a range of 200° C. to 400° C. for 1 to 20 hours, and 
 then performing cooling down to 150° C. at a rate of 15° C/h or less. 
 
     
     
       6. A wrought copper product provided with the titanium copper foil according to  claim 1 . 
     
     
       7. An electronic device component provided with the titanium copper foil according to  claim 1 . 
     
     
       8. The electronic device component according to  claim 7 , wherein the electronic device component constitutes an autofocus camera module. 
     
     
       9. An autofocus camera module comprising:
 a lens; and, 
 a spring member for elastically biasing the lens toward an initial position in an optical axis direction, and an electromagnetic driving means capable of driving the lens in the optical axis direction by generating an electromagnetic force against the biasing force of the spring member, 
 wherein the spring member is made of the titanium copper foil according to  claim 1 .